Power saving vacuum machine for improving vacuum ability of condenser of thermal power generator

ABSTRACT

A power saving vacuum machine serves for improving vacuum ability of a condenser of a thermal power generator. The vacuum machine being installed after the condenser and includes a least one valve installed on the vacuum primary tube for sealing a vacuum primary tube to prevent air from entering into the condenser; a front stage pump has an inlet connected to an air inlet tube; at least one root vacuum pump including a main root vacuum pump; the main root vacuum pump including an inlet and a vent opening; the inlet of the main root vacuum pump being connected to a rear end of the vacuum primary tube. The at least one root vacuum pump may be only one pump which is the main root vacuum pump, or the at least one root vacuum pump is a plurality of root vacuum pumps which are connected serially.

FIELD OF THE INVENTION

The present invention is related to vacuum technology for power plants, and in particular to a power saving vacuum machine for improving vacuum ability of a condenser of a thermal power generator.

BACKGROUND OF THE INVENTION

For a power plant by using thermal power to generate power, a condenser of a power generator is operated in vacuum. The condenser of a turbine is to assure that a power generator set has a preferred vacuum. The vacuum of the condenser will directly affect the efficiency of coal or gas combustion. For a 50 MW to 1000 MW power generator, if the vacuum is increased with a value of 1 kPa, the coal consumption for power generation of one kilowatt-hour can be reduced with a value of 2-4 grams.

The vacuum pumps used in current power plants have the following problems.

In the initial stage for actuation of the condenser of the water circulation pump, the vacuum ability is preferred, but then the vacuum of the condenser is increased, the pumping ability of the water circulation pump is decreased. When the pumping ability of the water circulation pump is deteriorated so that the vacuum of the condenser cannot be retained, the vacuum of the condenser will become worse. Efficiency of the turbine is decreased and the coal consumption in power generation is increased.

Current used vacuum power saving set of the condenser has finite ability. The object of the power saving set of the condenser is to retain the vacuum of the original system, while the pumping ability of the power saving set is finite. They only save power under the condition of retaining the vacuum not to reduce. But in many abnormal states, the vacuum of the condenser cannot be retained.

From many tests of the inventors of the present invention, it is found that when the pumping ability is increased, the vacuum of the condenser cannot be increased to be higher than the original vacuum of a big water circulation pump. Therefore, inventor of the present invention intends to provide a normal structure, which can improve the defects in the prior art to modify the current big water circulation pump and power saving vacuum set so as to increase the coal efficiency of current power generator.

SUMMARY OF THE INVENTION

Accordingly, for improving above mentioned defects in the prior art, the object of the present invention is to provide a power saving vacuum machine for improving vacuum ability of a condenser of a thermal power generator, wherein by the structure of the present invention, the pumping ability and the extreme vacuuming of the front stage pump can be promoted so as to increase pumping effect. By the present invention, the power plant can save more power and has preferred pumping affect with a higher vacuum. As a result, non-condensed air drained from the water circulation pump of a condenser can be removed effectively. Furthermore the present invention uses one or more high efficiency root vacuum pumps to increase vacuum ability of the former water circulation pump. The present invention serves to improve the vacuuming ability of a condenser of a power plant. The cost is low and effect is obvious so as to increase the power out of a power plant.

To achieve above object, the present invention provides a power saving vacuum machine for improving vacuum ability of a condenser of a thermal power generator, the power saving vacuum machine being installed after the condenser; the condenser including a vacuum primary tube for receiving external inputting vapor; the power saving vacuum machine comprising: a least one valve installed on the vacuum primary tube for sealing the vacuum primary tube to prevent air from entering into the condenser; a front stage pump including inlet and an outlet; the inlet of the front stage pump being connected to an air inlet tube; at least one root vacuum pump including a main root vacuum pump; the main root vacuum pump including an inlet and a vent opening; the inlet of the main root vacuum pump being connected to a rear end of the vacuum primary tube.

When the at least one root vacuum pump is only one pump which is the main root vacuum pump, the vacuum primary tube of the main root vacuum pump is connected to the inlet of the front stage pump through a third transfer tube; and wherein when the at least one root vacuum pump is a plurality of root vacuum pumps; the plurality of root vacuum pumps are connected serially; the plurality of root vacuum pumps includes a main root vacuum pump and at least one middle root vacuum pump; each middle root vacuum pump includes an inlet and a vent opening; the vent opening of the main root vacuum pump is connected to the inlet of a respective middle root vacuum pump through a first transfer tube; the vent opening of each middle root vacuum pump is connected to an inlet of a next middle root vacuum pump through a second transfer tube; a vent opening of the last middle root vacuum pump is connected to an inlet of the front stage pump through the third transfer tube.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an assembled schematic view about the elements of the present invention.

FIG. 2 is another assembled schematic view of the elements of the present invention.

FIG. 3 is a block diagram showing the control process and elements according to the present invention.

DETAILED DESCRIPTION OF THE INVENTION

In order that those skilled in the art can further understand the present invention, a description will be provided in the following in details. However, these descriptions and the appended drawings are only used to cause those skilled in the art to understand the objects, features, and characteristics of the present invention, but not to be used to confine the scope and spirit of the present invention defined in the appended claims.

With reference to FIGS. 1 to 3, the structure of the present invention is illustrated. The power saving vacuum pump set 300 is installed after a condenser 100. The condenser 100 may be an air condenser or a liquid condenser. The condenser 100 includes a vacuum primary tube 1 for receiving external vapor. The power saving vacuum pump set 300 includes the following elements.

At least one valve 2 is installed on the vacuum primary tube 1. The valve 2 includes an auto valve sheet (not shown) (such as an air driving valve sheet or an electromotive valve sheet) for sealing the primary tube 1 when the system is shutdown to prevent air from venting out. The valve 2 further includes a manual valve sheet (not shown) as a backup of the auto valve sheet. A returning tube 11 is installed at a front side of the valve 2 and is connected between the vacuum primary tube 1 and a section 12 for receiving returning water to prevent condensed vapor from flowing to the vacuum pump.

A front stage pump 7 includes an inlet 71 and an outlet 72. The inlet 71 of the front stage pump 7 is connected to an air inlet tube 75. The front stage pump 7 may be a water circulation vacuum pump (such as a big water circulation vacuum pump in a power plant, or other small water circulation vacuum pump in other power saving vacuum machine), or non water circulated front stage pump which drains air to outer side.

At least one root vacuum pump 30 includes a main root vacuum pump 3. The main root vacuum pump 3 includes an inlet 31 and a vent opening 32. The inlet 31 of the main root vacuum pump 3 is connected to a rear end of the vacuum primary tube 1.

As illustrated in FIG. 1, when the at least one root vacuum pump 30 only has the main root vacuum pump 3, the vacuum primary tube 1 of the main root vacuum pump 3 is connected to the inlet of the front stage pump 7 through a third transfer tube 75.

With reference to FIG. 2, when the at least one root vacuum pump 30 includes a plurality of root vacuum pumps 30. The plurality of root vacuum pumps 30 are connected serially. The plurality of root vacuum pumps 30 includes a main root vacuum pump 3 and at least one middle root vacuum pump 4. Each middle root vacuum pump 4 includes an inlet 41 and a vent opening 42. The vent opening 32 of the main root vacuum pump 3 is connected to the inlet 41 of a respective middle root vacuum pump 4 through a first transfer tube 35. The vent opening 42 of each middle root vacuum pump 4 is connected to an inlet 41 of a next middle root vacuum pump 4 through a second transfer tube 45. A vent opening 42 of the last middle root vacuum pump 4 is connected to an inlet 71 of the front stage pump 7 through a third transfer tube 75. The serial connected root vacuum pumps 30 serve to reduce the pressure difference in each pump so that the pump 30 will not deadly buckled due to overheat.

The first, second and third transfer tubes 75 can be equipped with a cooler or a heat exchanger 80 for preventing overheat of the proceeding pump so as to affect safety of the following vacuum pump.

The third transfer tube 75 is equipped with a check valve 6 for preventing air from flowing back to the root vacuum pump 30 or the condenser 100 due to any abrupt condition.

Practically, the front stage pump 7 may be water circulation vacuum pump or a liquid circulation pump used in the vacuuming of the condenser or the vacuum set for retaining vacuum of the condenser.

Each root vacuum pump 30 is any kind of root vacuum pump, such as air cooling root vacuum pump, two blade root vacuum pump, three blade root vacuum pump, etc.

When there are a plurality of root vacuum pumps 30. The vacuum primary tube 1 is arranged with a three way tube, one more added vacuum tube is connected to the inlet of the main root vacuum pump 3. When there is only one root vacuum pump 30, the vacuum tubes (not shown) to the inlet of a large water circulation pump (that is, the front stage pump 7) to the current power plant must be changed.

An outlet 72 of the front stage pump 7 is connected to a vapor separator 600 which is used to separate mixture of air and water outputted from the front stage pump 7 into air and water; the air is drained out enters into drain pipes (not shown); the water flows to a lower end of the vapor separator 600 which is formed as working water by the cooler of the heat exchanger 80 and then returns back to the front stage pump 7 as a working water for operation of the front stage pump 7.

The element of each root vacuum pump 30 is shown in FIG. 3. The root vacuum pump 30 is connected to a driving motor 92 for driving the root vacuum pump 30 which is further connected to a cooling device 91 for cooling water inputting to the root vacuum pump 30. The cooling device 91 further comprises a stage cooling tubes 912 or a heat exchanger 911 so as to reduce temperature of a pump casing 301. The root vacuum pump 30 is further arranged with a pressure detector 93 and a temperature detector 94. The pressure detector 93 is arranged at the inlet of the root vacuum pump 30 for detecting pressure of tubes of the root vacuum pump 30. The temperature detector 94 serves to detect temperature of the root vacuum pump 30. The pressure detector 93 and the temperature detector 94 are connected to a control device 95 which is further connected to the driving motor 92 and the cooling device 91. The control device 95 receives the data from the pressure detector 93 and the temperature detector 95 so as to control the driving motor 92 and the cooling device 91 to protect the whole structure in safety operation. The data from the pressure detector 93 and the temperature detector 95 can be transferred to a control center of a power plant (not shown).

The control device 95 controls the driving motor 92 to control the root vacuum pump 30 by variation of frequencies, which is suitable for the variation of the condenser 100. When the condenser 100 is in a good condition, the root vacuum pump 30 is operated in lower frequency. When the condenser 100 is not in good condition, the root vacuum pump 30 is operated in high frequency.

Advantages of the present invention are that by the structure of the present invention, the pumping ability and the extreme vacuuming of the front stage pump can be promoted so as to increase pumping effect. By the present invention, the power plant can save more power and has preferred pumping affect with a higher vacuum. As a result, non-condensed air drained from the water circulation pump of a condenser can be removed effectively. Furthermore the present invention uses one or more high efficiency root vacuum pumps to increase vacuum ability of the former water circulation pump. The present invention serves to improve the vacuuming ability of a condenser of a power plant. The cost is low and effect is obvious so as to increase the power out of a power plant.

The present invention is thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the present invention, and all such modifications as would be obvious to one skilled in the art are intended to be included within the scope of the following claims. 

What is claimed is:
 1. A power saving vacuum machine for improving vacuum ability of a condenser of a thermal power generator, the power saving vacuum machine being installed after the condenser; the condenser including a vacuum primary tube for receiving external inputting vapor; the power saving vacuum machine comprising: a least one valve installed on the vacuum primary tube for sealing the vacuum primary tube to prevent air from entering into the condenser; a front stage pump including inlet and an outlet; the inlet of the front stage pump being connected to an air inlet tube; at least one root vacuum pump including a main root vacuum pump; the main root vacuum pump including an inlet and a vent opening; the inlet of the main root vacuum pump being connected to a rear end of the vacuum primary tube; wherein when the at least one root vacuum pump is only one pump which is the main root vacuum pump, the vacuum primary tube of the main root vacuum pump is connected to the inlet of the front stage pump through a third transfer tube; wherein when the at least one root vacuum pump is a plurality of root vacuum pumps; the plurality of root vacuum pumps are connected serially; the plurality of root vacuum pumps includes a main root vacuum pump and at least one middle root vacuum pump; each middle root vacuum pump includes an inlet and a vent opening; the vent opening of the main root vacuum pump is connected to the inlet of a respective middle root vacuum pump through a first transfer tube; the vent opening of each middle root vacuum pump is connected to an inlet of a next middle root vacuum pump through a second transfer tube; a vent opening of the last middle root vacuum pump is connected to an inlet of the front stage pump through the third transfer tube.
 2. The power saving vacuum machine for improving vacuum ability of a condenser of a thermal power generator as claimed in claim 1, wherein the at least one valve includes one of an auto valve sheet and a manual valve sheet.
 3. The power saving vacuum machine for improving vacuum ability of a condenser of a thermal power generator as claimed in claim 1, wherein each through holes is a two blade root vacuum pump, a three blade root vacuum pump, or an air cooling root vacuum pump.
 4. The power saving vacuum machine for improving vacuum ability of a condenser of a thermal power generator as claimed in claim 1, wherein the front stage pump drains air out to exterior directly.
 5. The power saving vacuum machine for improving vacuum ability of a condenser of a thermal power generator as claimed in claim 1, wherein the front stage pump is one of a water circulation vacuum pump, a liquid circulation pump used in vacuuming of the condenser or a vacuum device for retaining vacuum of the condenser.
 6. The power saving vacuum machine for improving vacuum ability of a condenser of a thermal power generator as claimed in claim 5, wherein the outlet of the front stage pump is connected to a vapor separator which is used to separate mixture of air and water outputted from the front stage pump into air and water; the air is drained out and the water flows to a lower end of the vapor separator which is formed as working water by a cooler of a heat exchanger and then returns back to the front stage pump as a working water for operation of the front stage pump.
 7. The power saving vacuum machine for improving vacuum ability of a condenser of a thermal power generator as claimed in claim 2, wherein each root vacuum pump is connected to a driving motor and a cooling device for driving cooling water into the root vacuum pump.
 8. The power saving vacuum machine for improving vacuum ability of a condenser of a thermal power generator as claimed in claim 7, wherein the root vacuum pump is further arranged with a pressure detector and a temperature detector; the pressure detector is arranged at the inlet of the root vacuum pump for detecting pressure of tubes of the root vacuum pump; the temperature detector serves to detect temperature of the root vacuum pump; the pressure detector and the temperature detector are connected to a control device which is further connected to the driving motor and the cooling device; the control device receives the data from the pressure detector and the temperature detector so as to control the driving motor and the cooling device.
 9. The power saving vacuum machine for improving vacuum ability of a condenser of a thermal power generator as claimed in claim 1, wherein a returning tube is installed at a front side of the valve and is connected between the vacuum primary tube and a section for receiving returning water to prevent condensed vapor from flowing to the vacuum pump.
 10. The power saving vacuum machine for improving vacuum ability of a condenser of a thermal power generator as claimed in claim 1, wherein each of the first, second and third transfer tubes are equipped with a cooler or a heat exchanger.
 11. The power saving vacuum machine for improving vacuum ability of a condenser of a thermal power generator as claimed in claim 1, wherein the third transfer tube is equipped with a check valve for preventing air from flowing back to the root vacuum pump or the condenser due to any abrupt condition. 